Method and apparatus for v-bank filter bed scanning

ABSTRACT

Embodiments of the invention generally related to a method and apparatus for scanning a v-bank filter. In one embodiment, an apparatus for scanning a v-bank filter includes a hollow body having first and second ends. An outlet, formed at the second end of the body, is adapted for coupling a testing device to an interior volume of the body. A plurality of holes are formed through the body and are fluidly coupled to the interior volume. In another embodiment, a method for scanning a v-bank filter includes inserting a probe having a plurality of sample ports into a filter adjacent a filter pack, and traversing the probe along the filter pack. In yet another embodiment, a method for scanning a v-bank filter includes scanning a slot of a v-bank filter with a probe, and collecting samples of gas passing through the filter an into the probe.

RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.11/954,275, filed on Dec. 12, 2007 now U.S. Pat. No. 7,552,621, which isa divisional of U.S. patent application Ser. No. 11/552,409, filed onOct. 24, 2006 now U.S. Pat. No. 7,334,490, which claims benefit of U.S.Provisional Patent Application Ser. No. 60/729,643, filed Oct. 24, 2005by Thomas C. Morse, which are both incorporated by reference in theirentireties. Benefit of priority to all of the above-referencedapplications is claimed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a method and apparatus forv-bank filter bed scanning.

2. Description of the Related Art

Many contamination control applications having high airflow requirementsutilize v-bank filters over panel filters when laminar flow is not ofprimary concern. However, conventional manufacturing and validationpractices limit testing of v-bank to overall efficiency test due to theinability to accurately leak test (i.e., scan test) the filter media forpin hole leaks. The inability to scan test v-bank filters has beendocumented in an article published October, 2001 in Cleanrooms Magazineentitled “EN1822: THE STANDARD THAT GREATLY IMPACTED THE EUROPEANCLEANROOMS MARKET.” In the article, the author states that “ . . .HEPA/ULPA filters with V-shaped pleat packages cannot be scanned,because the measuring probe cannot be brought close enough to a possibleleak in the pleated package.”

However, many facilities are forced to utilize deep pleated filterproducts instead of v-bank filter products because of increasinglystringent validation requirements for contamination control that requirescan testing. As deep pleated filters generally do not have the airhandling capacity of v-bank filters, more filters may be required for agiven application, and more energy may be required to drive gas flowsthrough the filters. Thus, the use of deep pleated filters inapplications where v-bank filters could be utilized may realize higherfilter and energy usage costs.

Therefore, there is a need for a method and apparatus for scanningv-bank filter beds.

SUMMARY OF THE INVENTION

Embodiments of the invention generally relate to a method and apparatusfor scanning a v-bank filter. In one embodiment, an apparatus forscanning a v-bank filter includes a hollow body configured to extendbetween banks of a v-bank filter during testing. The hollow body hasfirst end and a second end. An outlet is formed at the second end of thebody and is adapted for coupling a testing device to an interior volumeof the body. A first plurality of holes are formed through the body withare fluidly coupled to the interior volume.

In another embodiment, a method for scanning a v-bank filter isprovided. In one embodiment, the method includes inserting a probehaving a plurality of sample ports into a filter adjacent to a filterpack, and traversing the probe along the filter pack.

In another embodiment, a method for scanning a v-bank filter includesscanning a slot of a v-bank filter with a probe, and collecting samplesof gas passing through the filter an into the probe.

In one embodiment, a probe for scan testing a v-bank filter includes ahollow body having an interior volume, a first end and a second end. Thehollow body is configured to extend between the banks of a v-bank filterduring testing. An outlet formed at the second end of the body isadapted for coupling an interior volume of the body to a testing device.A first plurality of apertures are formed through the body and fluidlycoupled to the interior volume.

In another embodiment, a probe for scan testing a v-bank filter includesan elongated hollow body sealed at a first end and having a port at asecond end. A tapered slot is formed through a wall of the body, whereina wide end of the tapered slot is orientated towards the first end ofthe body.

In another embodiment, a method for testing a v-bank filter is providedthat includes inserting a probe between two banks of filtration media ofa v-bank filter, and traversing the probe along the banks, andsimultaneously providing samples from each bank individually to a testinstrument.

In another embodiment, a method for testing a v-bank filter is providedthat includes providing a challenge to a v-bank filter having at leasttwo adjacent banks of filter media arranged in a “v” configuration,scanning a probe across an opening defined between the adjacent banks offilter media, sampling air passing through the banks of filter media andinto the probe, determining if a sample is indicative of a leak.

BRIEF DESCRIPTION OF THE DRAWINGS

The teachings of the present invention can be readily understood byconsidering the following detailed description in conjunction with theaccompanying drawings, in which:

FIGS. 1A-B, 2-3, 4A-B, 5A-B and 6 are various views of differentembodiments of a probe suitable for scan testing a v-bank filter;

FIG. 7 is another embodiment of a probe suitable for scan testing av-bank filter;

FIGS. 8-11 are images of a probe of the present invention engaged with av-bank filter to facilitate scan testing; and

FIGS. 12A-B are another embodiment of a probe suitable for scan testinga v-bank filter.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements and features of oneembodiment may be beneficially incorporated in other embodiments withoutfurther recitation.

It is to be noted, however, that the appended drawings illustrate onlyexemplary embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

DETAILED DESCRIPTION

Embodiments of the invention are suitable for scan testing v-bankfilters for pin-hole leaks. Although the filter illustrated herein is aFILTRA 2000™ v-bank filter available from Camfil Farr, Inc., it iscontemplated that the testing apparatus and method may be utilized toscan test v-bank filters having other configurations. A scan probedeveloped to facilitate scan testing enables reasonable scan rate (i.e.,in the range of about 1-2 inches per second (25.4-50.8 millimeters persecond)) for manual scan operations and may further be adapted for usein automatic or semi-automatic scan applications.

Probe Design

The V-bed media pack configuration creates obstacles in the scan testprocess and probe design, as compared to a conventional box-style mediapacks, where the face of the entire pack is in a single plane. Inconventional box-style filters, the probe generally consists of a tubewith an integral transition through which the sample is drawn. Thetransition is generally square or rectangular. The design of this typeof sampling probe is such that the localized velocities across thesampling plane of the probe are equivalent, resulting in uniform airflowacross the sampling plane.

In the present invention, a probe allows adjacent media packs to bescanned simultaneously. Although this isn't necessary, it is desirablebecause it reduces the number of “passes” per filter that an operatorhas to make with the probe when testing a filter. It is contemplatedthat the probe may be configured to scan only one media pack in a singlepass.

FIGS. 1-8 depict various views of probes suitable for scan testing av-bank filter. The samples taken during the scan may be utilized fordetermining the location of pin-hole leaks greater than a predeterminedcriteria or filter efficiency. Referring first to a probe 100 depictedin FIGS. 1A-B, the probe 100 is generally a tube or other hollow body102 sealed at a first end 104 and having a port 106 at a second end 108.The shape of the body 102 is configured to allow the first end 104 ofthe probe 100 to be positioned between adjacent banks of a v-bankfilter. The port 106 is generally adapted to coupling to a testinstrument, such as a photometer, particle counter or other instrumentsuitable for leak detection or efficiency measurement. In oneembodiment, a length of stainless steel tubing is bent into aconfiguration that fits into the “V” defined by the filter banks, forexample, a “V” or triangle shape. In other embodiment, the tubing may bestraight or wedge shaped. A plurality of apertures 110, such as holes orslots, are formed, for example by drilling, along outward facing side ofat least one leg of the probe 100. The number, size and spacing of theapertures 110 are selected to allow sampling along the length of themedia bank perpendicular to the direction of scan. As such, the lengthof the probe having the apertures 110 formed therethrough is generallyequal to the length of the media bank for which the probe is intended tobe used. Thus, the apertures 110 on each leg face in oppositedirections. In the embodiment depicted in FIG. 1, each leg of the probe100 includes a linear arrangement of apertures 110. The interior volumeof each leg is fluidly coupled to the port 106 such that samples takenthrough the apertures 110 may be provided to the test instrument.

The apertures 110 may be of a single, different or a combination ofsizes. In one embodiment, the orifice, or plan area of the apertures 110formed through the probe wall is reduced between holes extending alongthe length of the probe towards the first end 104 to account forpressure losses due to the sample being drawn from the second end 108 ofthe probe. In one embodiment, the apertures 110 include at least twogroups of holes and/or slots having different orifice sizes. In theembodiment depicted in FIG. 1B, the apertures 110 include a far group ofholes 110C at the first end 104 of the probe 100 furthest from thephotometer that have a larger diameter (orifice) than the diameter of anear group of holes 110A disposed closest to the second end 108 (andphotometer), while a middle group of holes 110B disposed in themidsection of the probe 100 have a diameter somewhere between those thediameters of the apertures 110 closest and farthest from the second end108. For example, the apertures 110 may include near group of holes 110Ahaving a diameter of about 0.018-0.062 inches (0.45-1.57 mm), middlegroup of holes 110B having a diameter of about 0.055-0.077 inches(1.40-1.96 mm), and a far group of holes 110C having a diameter of about0.062-0.093 inches (1.57-2.36 mm). Increasing the hole diameter alongthe length of the probe 100 results in a more uniform (andrepresentative) sample along the length of the probe. Similar probescould be designed using an aperture 110 configured as a slot thatchanges in width along the length of the probe (e.g., tapers towards thefirst end 104), or by using perforated material along the length of theprobe that uses larger holes and/or different hole spacing along thelength of the probe, in order to achieve the same results.

FIGS. 2-3 show the probe 100, including an integral handle 150 andguides, 112 to locate the probe 100 in the “V” of the filter during ascan of the filter. These guides 112 allow the probe 100 to maintain ata predefined distance from each media pack by limiting the distance thefirst end 104 of the probe can be inserted into the filter. The guides112, such as bars, rods, rollers, bearing, slides, tabs or otherfixtures (as seen in FIGS. 2-3 and 8-11), ensure the probe remainsreasonably centered between the media packs, thereby eliminatingpotential damage the media banks by inadvertent contact with the probe100 during insertion or scanning, and also ensuring that the distancebetween the probe and the face of the media pack is maintained at therequired distance (or range).

In one embodiment, the probe 100 is fabricated from one or more hollowtubes 180 formed in a V-shape to fit between the pleated media packs.The tubes 180 are coupled near the second end 106 at a tee 182, whichextends to the port 108. The apertures 110 of the probe may be designedas a plurality of slots or holes 110A-C (as shown in FIGS. 1A-B, and2-3), staggered holes 410 (as shown in FIGS. 4A-B), one or more taperedslots 510 (as shown in FIGS. 5A-B), staggered slots or holes 610 (asshown in FIG. 6) or other configurations to allow air sampling within 1″(25.4 mm) of the face of the media pack, which is generally an industryacceptable distance between the media pack and a sampling probe. Inembodiments wherein a slot is utilized, the aperture 110 may be a singleslot 510 as shown in FIGS. 5A-B, although a plurality of slots may beutilized. The geometry of the probe 100 may be modified in cases wherestandards or industry practices would require that the probe be locatedcloser to the media pack during scan testing. In embodiments wherein thebody 102 is a tube 180, the rounded surface (outer diameter of the tube180) through which the apertures 110 are formed provides protectionagainst damage to the filter media in the advent that inadvertentcontact between the probe and media is made, particularly as compared toconventional rectangular probes having squared corners.

In the embodiment depicted in FIG. 4A-B, a probe 400 includes a body 102having legs 402, 404 that meet at a first end 104. The legs 402, 404flare outward from the first end 104 toward a second end 108. Each ofthe legs 402, 404 includes a separate port 406A, 406B at the second end108 for coupling each leg separately to a test instrument. Since samplestaken through apertures 410 (formed in the legs 402, 404 as describedabove) are separately sampled, leak detection of the specific bank offilter media proximate an individual leg 402, 404 may be determined.

The apertures 410 may be staggered in size so that the apertures havinglarger orifice diameters are closer to the first end 104. In oneembodiment, the apertures 410 are configured similar to the apertures110 described with reference to FIG. 1B.

In another embodiment depicted in FIGS. 5A-B, a probe 500 includes abody 102 that may be configured as either the probe 100 or 400 describedabove. The probe 500 includes a slot 510 formed in the outward facingsides of the legs of the body 102. In one embodiment, the slot 510 maybe tapered such that the wide end of the slot 510 is proximate the firstend 104 of the body 102.

In another embodiment depicted in FIG. 6, a portion of a probe 600 isshown. The body 102 of the probe 600 that may be configured as eitherthe probe 100 or 400 described above. The probe 600 includes a pluralityof staggered apertures 610, shown in FIG. 6 as slots. The apertures 610formed in the outward facing sides of the body 102 such that a portionof one aperture 610 overlaps the adjacent aperture. In one embodiment,the apertures 610 closer the first end (104) of the body 102 may havemore in open area than the apertures 610 is proximate the second end(106).

In another embodiment depicted in FIG. 7, the probe 700 has arectangular shape. The width of the probe is such that it wider than thewidth of the slot 702 defined at the wide end of the Vee where air exitsbetween the media packs 704 of a v-bank filter. The probe 700 mayinclude one or more guides 706 to align the probe with the slot, such asa rod, roller, bar or other locating features coupled to the open end ofthe probe 706 as shown in FIG. 7. The probe 700 is placed as near aspossible to the slot 702 in order to eliminate potential bypass aroundthe probe. Scan testing is conducted by moving the probe along the slot.This is very similar to scan testing a conventional HEPA filter, exceptthe probe is used to scan the slot instead of the media pack. It iscontemplated that scan data may also be utilized to calculate filterefficiency.

In another embodiment depicted in FIGS. 12A-B, a probe 1200 suitable forscanning a v-bank filter is illustrated. The probe 1200 includes a body1202 having at least one sample port 1204. In the embodiment depicted inFIGS. 12A-B, four sample ports 1204 are shown.

Each sample port 1204 includes a sample entrance port 1206 and a sampleexit port 1208. A fitting 1210 is coupled to the body 1202 at the exitport 1208 to facilitate coupling the port 1204 to a test instruments,such as a photometer or other suitable device.

At least one guide 1212 is provided on the sample entrance port side ofthe probe 1200. The guide 1212 facilitates alignment of the probe 1200to the filter as described above. In the embodiment depicted in FIGS.12A-B, two guides 1212 in the form of bars secured perpendicular to themajor axis of the probe 1200 and aligned with the scan direction areprovided.

Validation of Probe & Method of Testing V-Bank Filter

The probe of the present invention was demonstrated as being effectivefor locating leaks. A FILTRA 2000 v-bank filter was utilized during thetest. The filter was installed in a test rig and challenged with PAO.The filter was then manually scan tested using the probe describedabove. The testing is detailed below.

Procedure—Insertion Style Probe

In one embodiment, a probe, such as the probes 100, 400, 500, wasutilized to scan test a Filtra 2000™. The probe was used to scan betweenthe banks of filter media within the Vee's from the downstream side ofthe V-bed filter.

Two holes were intentionally placed in a FILTRA 2000™ v-bank filterusing a mechanical pencil with a 0.5 mm diameter lead to create a leakin a known location. “Hole A” was created in the media pack on thedownstream side of the filter, on the downstream side of the media pack,at a location approximately 1 inch (25.4 mm) from the vertical extrusionmember. “Hole B” was created in the media pack on the upstream side ofthe filter, on the upstream side of the media pack, at a location verynear the vertical extrusion member. Holes were created in thoselocations because they represent locations where leaks are generallyconsidered difficult to detect.

The test rig utilized to perform the scan test generally includes avariable frequency drive on the test rig was adjusted until a pressuredrop across the air flow station (AFS) was approximately 0.452 incheswater gage (w.g.) (0.113 kPa) as measured using an Alnor Micromanometer.This pressure drop across the filter is indicated of approximately 2000cubic feet per minute (56.6 cubic meters per minute) of flow through thefilter.

An ATI TDA-5B thermal generator was used to generate PAO aerosol thatwas injected into the inlet of the blower. An ATI TDA-2E photometer wasused to obtain an upstream sample in the transition immediately upstreamof the filter. The blower, aerosol generator and photometer were allowedto warm up for approximately 20 minutes allow steady-state operation tobe reached.

The aerosol generator was turned on, and adjusted to obtain between40-50 micrograms/liter. This range was chosen because various industrystandards and recommendations (for examples, IEST and ATI) recommendscanning with an aerosol challenge ranging from 10-100 micrograms/liter.The upstream challenge concentration was measured with the photometer.The filter was scan tested using the prototype probe connected to thephotometer and the results were recorded as shown in Table 1 below. Thescan was performed by manually inserting the probe into the filter suchthat the aperture(s) is facing the filter pack to be tested. The probeis then advanced across the pack to test the media for pin-hole leaks.The leak threshold may be set per IEST standards or other test protocol.

Equipment Used

-   -   Test Filter: FILTRA 2000™, available from Camfil Farr, Inc.        -   Model Number: FA1570A-01-01-09        -   Part Number: 855010095        -   Serial Number: A116084-008        -   Label Efficiency: 99.998%        -   Label Pressure Drop: 1″ w.g. (0.25 kPa)        -   Rated cfm: 2150 (60.9 cubic meters per minute)    -   Pressure Indicator: ALNOR MicroManometer (digital        micromanometer)        -   Model: AXD 550        -   Instrument I.D.: 66303        -   Calibrated: Jun. 26, 2003        -   Calibration Due: Jun. 26, 2004    -   Leak Detection Equipment: ATI Analog Photometer        -   Model: TDA-2E        -   Serial No.: 8462        -   Calibrated: Oct. 31, 2003        -   Calibration Due: Oct. 31, 2004    -   Aerosol Generators:        -   ATI Thermal Generator            -   Model: TDA-5B            -   Serial No.: 15769        -   ATI Laskin Nozzle Generator            -   Model: TDA-4BL            -   Serial No.: 14718

TABLE 1 Parameter Result AFS dP: 0.452 System Flowrate ~2000 cfm (56.6cubic meters per minute) Aerosol Type Thermal PAO Upstream AerosolConcentration 40 μg/l Photometer Scale Setting 0.1% Approximate ManualScan Speed ~1 in/sec (25.4 mm/sec) “Hole A” Leak Detected** “Hole B”Leak Detected** Background Concentration* 0.04% *The “backgroundconcentration” was constantly present and attributed to the so-called“Bleed Through” phenomena. Essentially, it's a result of using thermallygenerated aerosol (with a particle diameter near the most penetratingparticle size (MPPS), or 0.12 μm) for the challenge and operating thefilter at such a high flowrate. The IEST recommendations were developedforsystems operating at approximately 90 feet per minute (fpm) (27.4meters per minute) superficial velocity. In this test, the superficialmedia velocity is approximately 160 fpm (48.8 meters per minute).Furthermore, per IEST-RP-CC034.1, a Laskin nozzle generator (generatingparticles in the range of 0.6-0.7 μm diameter) is recommended forchallenging this type of filter. **IEST-RP-CC034.1 specifies a maximumpenetration of 0.01%. It was not possible to base the presence of a leakon that penetration since the “background concentration” was higher than0.01%. However, when the probe passed over the leaks, the photometerregistered penetrations exceeding 0.1%, obviously indicating that leakswere present.

After scan testing was completed using an upstream challenge ofapproximately 40 μg/l, the output to the aerosol generated was adjustedto approximately 10 μg/l, and the filter was scanned again. That testyielded the same results as the test conducted at 40 μg/l. In order tobe consistent with recommendations of IEST-RP-CC0034.1, testing wasconducted using an ATI TDA-4BL Laskin Nozzle Generator. The results ofthat test are shown in Table 2.

TABLE 2 Parameter Result AFS dP: 0.452 System Flowrate ~2000 cfm (56.6cubic meters per minute) Aerosol Type Cold PAO Upstream AerosolConcentration 12 μg/l Photometer Scale Setting 0.01% Approximate ManualScan Speed ~1 in/sec (25.4 mm/sec) “Hole A” Leak Detected** “Hole B”Leak Detected** Background Concentration n/a

The “background concentration” due to bleed-through was not a problemwhen testing with the Laskin Nozzle generator. “Hole A” and “Hole B”were easily detected. Thus, due to “bleed through” effects, there is abackground concentration present during testing using thermallygenerated PAO, which exceeds the maximum allowable penetration asrecommended by IEST-RP-CC0034.1. This may be overcome by using a higherefficiency filter, such as an ULPA filter, which is designed to behighly efficient in removing 0.12 μm particles. The down side of this isthe increase in pressure drop and increase in cost. As designed, theprobe is effective in locating small pinhole leaks in the filter, withthe filter operating at design flowrates and challenged with cold PAOgenerated with a Laskin Nozzle generator.

Procedure—Above Slot Style Probe

In another embodiment, the probe such as the probes 700, 1200 wasutilized to scan test a Filtra 2000™. The probe was used to scan theopening between the Vee's on the downstream side of the V-bed filterwithout penetrating between the Vee's. The probe height was designed sothat it extended beyond the media pack and overlapped the channel oneach side of the Vee. For the test data provided below, the opening ofthe inlet sample port 1206 is 5.406 inches high×0.125 inches wide (137mm×3.18 mm).

Design of the probe was confirmed as effective in locating leaks using aFiltra 2000™ was installed in a test rig and challenged with PAO. Thefilter was automatically scanned with the probe assembly that wascoupled to a lead screw assembly which was rotated by a small servomotor. This allowed for precise control of the rotational speed of themotor and therefore accurate and precise control of the linear speed ofthe probe assembly. The testing is detailed below.

Two holes were intentionally placed in a Filtra 2000 using capillarytubes with an internal diameter (I.D.) of 0.020″. “Hole 1” was createdin the media pack on the downstream side of the filter, on thedownstream side of the media pack, at a location approximately 6″ fromthe side of filter. “Hole 2” was created in the media pack on theupstream side of the filter, on the upstream side of the media pack, ata location approximately 1″ from the side of the filter. Holes werecreated in those locations because they represent locations where leaksare generally difficult to detect.

The variable frequency drive on the test rig was adjusted until theflowrate was approximately 2,400 cfm. An ATI TDA-4B Lite aerosolgenerator was used to generate PAO aerosol that was injected through theaerosol injection ring in the containment housing. The autoscan controland sampling system was used to conduct leak testing using a LighthouseSolair 3100+ laser particle counter on the 0.3 micron size range.Results are provided in the Table below.

TABLE 3 Test Results Operating at 0.25 inches/sec Scan Speed ParameterResult System Flowrate 2,400 cfm (70 meters per minute) Aerosol TypeCold PAO Upstream Aerosol Concentration 460,000,000 particles per cubicfoot (13,025,750 particles per cubic meter) (0.3 micron diameter) ScanSpeed 0.25 in/sec (.64 cm/sec) “Hole 1” Leak not detected “Hole 2” Leaknot detected

TABLE 4 Test Results Operating at 0.125 inches/sec Scan Speed ParameterResult System Flowrate 2,400 cfm (70 meters per minute) Aerosol TypeCold PAO Upstream Aerosol Concentration 460,000,000 particles per cubicfoot (13,025,750 particles per cubic meter) (0.3 micron diameter) ScanSpeed 0.125 in/sec (0.32 cm/sec “Hole 1” Leak detected @ 6.6″ with0.014″ penetration “Hole 2” Threshold leak detected with 0.9″ of 0.008%penetration

As designed, at rated airflow of 2,400 cfm and an upstream challengeconcentration of 460,000,000 particles per cubic foot of 0.3 microndiameter, the system was capable of locating pinhole leaks at a scanspeed of 0.125 inches/sec, but not 0.250 inches/sec. Using higheraerosol challenge upstream may allow leaks to be located at faster scanspeeds, since the amount of challenge coming through the leak would behigher and detected more easily. Also, at lower airflows the system iscapable of finding leaks at faster scan speeds since the particlespassing through the pinhole are not diluted downstream of the filter byclean air and are thus more easily detected during scanning.

Scan speeds of up to about 0.1875 inches/sec (0.48 cm/sec) havedemonstrated to produce acceptable scanning results. Thus, in systemshaving an operational velocity of less than or equal to 2400 cubic feetper minute, a scan speed of less than or equal to about 0.1875 inchesper second may be utilized to detect leaks in v-bank filters wherein theupstream challenge is about 300,000,000 particles per cubic foot (about8,495,050 particles per cubic meters) in a 2,400 cfm flow. It iscontemplated that the scan rate may rise at lower operational velocitiesand/or at higher challenges.

Thus, a method and apparatus has been provided that enables scan testingof v-bank filters. Advantageously, the invention will allow the use ofv-bank filters in applications where testing for pin-hole leaks isrequired.

Although various embodiments which incorporate the teachings of thepresent invention have been shown and described in detail herein, thoseskilled in the art can readily devise many other varied embodiment thatstill incorporate these teachings.

1. A probe for scan testing a v-bank filter, comprising: a hollow bodyhaving an interior volume, a first end and a second end, the hollow bodyhaving a first side and a second side tapering from the second end tothe first end, the hollow body configured to extend between banks of av-bank filter during testing; an outlet formed at the second end of thebody and adapted for coupling to a testing device the interior volume;and a first opening formed through the first side of the body andfluidly coupled to the interior volume.
 2. The probe of claim 1, whereinthe first opening comprises: a plurality of linearly aligned apertures.3. The probe of claim 1, wherein the first opening is linearly arranged.4. The probe of claim 1, further comprising: a guide coupled to the bodyand configured to prevent the body from extending more than a predefineddepth between the banks of the filter.
 5. The probe of claim 1, whereinthe first opening comprises: a first slot formed through the first sideof the body.
 6. The probe of claim 5, wherein the first slot is atapered slot having a wide end oriented towards the first end of thebody.
 7. The probe of claim 1, further comprising a second openingcoupled to the interior volume of the body, the second opening formed inthe second side of the body.
 8. The probe of claim 7, wherein the firstopening is one of a first plurality of apertures formed in a first legof the body and the second opening is one of a second plurality ofapertures formed in a second leg of the body, the legs defining an acuteangle therebetween.
 9. The probe of claim 8, wherein at least two of thefirst plurality of apertures have different effective orifice sizes. 10.The probe of claim 9, wherein the first plurality of apertures arearranged in order of orifice size.
 11. A probe, comprising: an elongatedhollow body sealed at a first end and having a port at a second end; afirst tapered slot formed through a first wall of the body, wherein awide end of the first tapered slot is orientated towards the first endof the body.
 12. The probe of claim 11, further comprising: a secondopening formed through a second wall of the body opposite the firstwall.
 13. The probe of claim 12, wherein the second opening comprises: asecond tapered slot formed through the second wall of the body, whereina wide end of the second tapered slot is orientated towards the firstend of the body.